Swaging operations are employed in numerous different processes, typically assembly processes. Broadly stated, a swaging operation typically involves the plastic deformation of a first component into engagement with a second component to connect the first and second components together.
A swaging operation is employed, for example, in the aerospace industry to fasten a threaded insert into a hole formed in a larger structure such as a casting. Certain large aerospace structures such as castings can be extremely expensive and cost one million dollars or more. Many such expensive structures are employed in applications that require periodic disassembly, such as for maintenance, inspection, and the like. Threaded fasteners employed with such structures often include one or more known self-locking features such as are provided with special coatings or platings on the threads and special thread configurations. The repeated threading and unthreading of such threaded fasteners onto and off of a larger structure has a tendency to cause wear to the threads, particularly if the fasteners include a self-locking feature.
It is thus known to provide threaded inserts for use in conjunction with such larger structures such as castings. These inserts are hollow cylindrical members having thin walls that are threaded both internally and externally, with a counterbore being formed at one end of the insert. Such inserts are threadably received in a threaded and counterbored hole formed in the larger structure. The counterbored region of the insert is swaged radially outwardly into fastening engagement with the counterbored region of the larger structure to affix the insert into the hole formed in the structure. A threaded fastener can then be threadably received in the internal threads of the installed insert.
Such threaded inserts often are formed out of relatively hard materials such as titanium and nickel based alloys. These alloys are relatively harder than the larger structures which often are made of a relatively softer material such as aluminum. The internal threading of the insert often includes a self-locking feature such as the aforementioned coating or plating on the threads or the special thread configuration, and such internal threading typically is guaranteed to last a certain number of threading and unthreading cycles, such as fifteen cycles. Once an installed insert has undergone the guaranteed number of cycles, i.e., has had a threaded fastener threaded into and unthreaded from the internal threads the guaranteed number of times, the insert is removed in a known fashion from the relatively larger structure and is replaced with a new insert of the same configuration. The new insert would then again provide a given number of threading and unthreading cycles before it too would need to be replaced.
Since the insert is swaged to the relatively larger structure instead of employing a self-locking feature between it and the relatively larger structure, the repeated replacement of the threaded inserts does not raise an issue of thread wear as to the relatively larger structure itself. The swaging of such threaded inserts has not, however, been without limitation. Threaded inserts typically have been swaged to the relatively larger structure by hammering. Such hammering is imprecise and raises a substantial risk of damaging the relatively larger structure which, as set forth above, can be extremely expensive. Such hammering can also be extremely difficult to perform in the cramped confines of many aerospace applications.
Alternative swaging operations have met with little success. One such type of alternate swaging operation involved threadably mounting a swaging tool to the internal threading of an insert and applying forces in a threading direction to plastically deform the counterbored portion of the insert into swaged engagement with the counterbored portion of the relatively larger structure. Such systems can damage the coating or plating on the internal threads and thus interfere with and reduce the number of threading and unthreading cycles the insert can withstand. Additionally, some inserts include radially outwardly protruding structures on the external surface thereof in the region of the counterbore, and during the swaging operation the protruding structures are received in pre-broached holes formed in the counterbore of the relatively larger structure. Prior to the swaging operation the protruding structures must be rotationally aligned with the pre-broached holes. Such rotational alignment is difficult to maintain if a swaging operation requires the threadable cooperation of a swaging tool with the internal threads on an insert.
It is thus desired to provide an improved machine that can perform a non-impact swaging operation on first component, such as a threaded insert, to swage it and a second component together. Such an improved machine preferably would not rely upon threadable cooperation with the internal threads of an insert and would not have a tendency to disturb rotational alignment between protruding structures on a threaded insert and corresponding pre-broached holes formed on the second component, which may be a relatively larger structure. The machine would desirably also be made up of tooling that is mounted to a known actuator, such as a pneumatic gun of the type already employed for various purposes in aerospace applications.